For the Cinnamon Sugar Swirl:

• ½ cup brown sugar (packed): Brown sugar is the heart of that irresistible cinnamon swirl. The molasses in brown sugar adds a depth of flavor and moisture that granulated sugar simply can’t replicate. Packing it ensures you get the right amount for that rich, gooey center.
• 2 teaspoons cinnamon (ground): Cinnamon is the star of the show, lending its warm, comforting aroma and flavor to both the swirl and the cake itself. Ground cinnamon is readily available and blends seamlessly into the sugar mixture.

For the Coffee Cake Loaf:

• 2 cups all-purpose flour: All-purpose flour provides the structure for our loaf. It has a moderate protein content, which results in a tender yet sturdy crumb. Make sure to measure it correctly – spooning it into your measuring cup and leveling it off is the best way to avoid using too much flour, which can lead to a dry cake.
• 1 tablespoon baking powder: Baking powder is a chemical leavening agent that creates lift and lightness in the cake. It’s essential for achieving that airy, tender crumb we’re after. Make sure your baking powder is fresh for optimal results.
• 1 teaspoon baking soda: Baking soda is another leavening agent, and it also reacts with the buttermilk in the recipe to create a slightly tangy flavor and contribute to the cake’s moistness. Like baking powder, ensure it’s fresh for the best rise.
• ¼ teaspoon salt: Salt might seem insignificant, but it’s crucial for balancing the sweetness and enhancing the other flavors in the cake. It prevents the cake from tasting flat and brings out the richness of the butter and vanilla.
• ¼ cup butter (unsalted, softened): Unsalted butter allows you to control the overall saltiness of the recipe. Softened butter is essential for proper creaming with the sugar, creating a light and airy base for the cake. Make sure it’s truly softened, but not melted, for the best texture.
• ¾ cup sugar (granulated): Granulated sugar provides sweetness and also contributes to the cake’s texture. When creamed with butter, it creates air pockets that help the cake rise and become light and fluffy.
• 2 large eggs (room temperature): Eggs add richness, moisture, and structure to the cake. Using room temperature eggs is important because they emulsify more easily with the other ingredients, resulting in a smoother batter and a more even texture in the baked loaf.
• 1 cup buttermilk: Buttermilk is the secret ingredient for a truly moist and tender coffee cake. Its acidity reacts with the baking soda, creating a tender crumb and a slight tang that complements the sweetness perfectly. If you don’t have buttermilk, you can make a quick substitute (see FAQ section!).
• 1 teaspoon vanilla extract: Vanilla extract enhances the overall flavor profile of the cake, adding a warm, comforting note that ties everything together. Use pure vanilla extract for the best flavor, or vanilla bean paste for an even richer vanilla experience.